Slub yarn and process therefor



y 25, 1967 P. F. MARSHALL SLUB YARN AND PROCESS THEREFOR Filed Oct. 20, 1965 United States Patent 3,332,227 SLUB YARN AND PROCESS THEREFOR Preston F, Marshall, Walpole, Mass., assignor to The Kendall Company, Boston, Mass., a corporation of Massachusetts Filed Oct. 20, 1965, Ser. No. 498,239 11 Claims. (Cl. 57-144) This invention relates to a novelty yarn of the slub type, and to a process for producing such a yarn. More particularly, it relates to a yarn and process wherein a frangible core strand is combined with a wrapping strand in a particular manner, after which the core strand is ruptured by tension and the wrapping strand becomes the load-bearing element of the combination, a part of the wrapping strand being simultaneously formed into slubs or nubs.

By slubs or nubs is meant that at intervals a portion of the wrapping strand is entangled upon itself to form a strand segment of heavier denier than the remaining portion of the 'wrapping strand. A slub is generally defined as a thickened portion of a yarn possessing tapered leading and trailing ends, while a nub is a more abrupt discontinuity. Both slubs and nubs are deliberately produced in novelty yarns in order to impart texture and surface interest, as well as color contrast, in fabrics for apparel, upholstery, drapery, and numerous other well-known uses.

'Slub and nub yarns are conventionally produced by feeding a core strand and simultaneously overfeeding a wrapping strand into a twisting mechanism, and periodically arresting or slowing the feed of the core strand while continuing the overfeed of the wrapping strand to cause the overfed wrapping strand to accumulate around the core strand, whereby the finished combination yarn is characterized by thick and thin segments. Many variations on this process are known, as are control devices and methods for randomizing the periodicity of the slubs and nubs, including computer controlling.

I have found that I can produce what I hereinafter term a variable denier yarn, wherein the thick and thin segments are randomly spaced, by a novel and inexpensive process.

It is, therefore, among the objects of this invention to provide a novel method for producing a variable denier yarn, and to employ such a yarn in the fabrication of textiles, either alone or plied or wrapped with an auxiliary strand.

The basic steps in the process of this invention comprise:

(l) Disposing around a frangible core strand a wrapping strand, disposed around said core strand in the form of doubled-back loops wound with false twist for a multiplicity of turns around said core strand.

(2) subjecting the thus-formed basic yarn to tension sufficient to rupture the frangible core strand at intervals, whereby the former wrapping strand becomes the loadbearing strand, a portion of the wrapping strand being entangled upon itself in the form of segments of heavy denier while another portion of the wrapping strand maintains its original denier.

The novel yarn thus produced may be used directly in knitting operations: in fact, the basic wrapped yarn may, by a tension device on a knitting machine, be drafted to rupture the core strand and form the yarn of the invention while said yarn is being fed to the machine. More commonly, the basic yarn is drafted to rupture the core strand in a tensioning yarn-twisting device While it is being plied with a third strand, for enhanced novelty effect. Instead of a yarn-twister, a wrapping device suitable for covering elastic yarns may be employed, such devices commonly being designed to draft a core strand under tension while simultaneously wrapping the core strand with one or 3,332,227 Patented July 25, 1967 more covering strands. Alternatively, the drafting may be done by feeding the basic yarn, under tension suflicient to break the core strand at intervals, into a vortex cell in a process set forth in US. Patent 3,082,591, to the instant inventor. Still another tension-applying device for rupturing the core strand of the basic yarn is a core-spinning device, wherein a filamentary strand is combined under twist and tension with, for example, a strand of roving of staple fibers.

=By frangible core is meant a core strand which can be ruptured by the exercise of moderate levels of tension, at which levels the wrapping strand remains unbroken. By basic yarn is meant the combination of such a core strand with at least one wrapping strand, with the core strand serving as the load-bearing member.

The invention will be better understood by reference to the following description and drawings, in which:

FIGURE 1 represents the basic yarn, antecedent to the rupturing process.

FIGURE 2 is an idealized representation of the yarn of FIGURE 1 at the moment of rupture of the core strand.

FIGURE 3 is a representation of the yarn of the present invention.

FIGURE 4 is a schematic representation of one form of apparatus suitable for converting the basic yarn of FIG- URE l to the yarn of the invention, FIGURE 3.

FIGURE 5 represents the yarn of the present invention plied with an auxiliary strand.

FIGURE 6 is a schematic cross-section of one apparatus used to make the yarn.

FIGURE 7 represents the yarn of the present invention with an additional wrapping strand.

Referring to FIGURE 1, the basic yarn is formed by combining a frangible core strand 10 with at least one wrapping strand 12, the wrapping strand being disposed around the core strand in the form of doubled-back loops 14 wound with false twist for a multiplicity of turns around the core strand. By false twist is meant that in the wrapping process, as set forth in my US. Patent 3,082,- 591, there is no rotation of the wrapping strand end around the core strand except in double-ended or loop form; hence, regardless of how heavily wrapped the core strand appears to be, there is no true net twist of wrapping strand around the core strand.

FIGURE 2 represents the yarn of FIGURE 1 at the instant when sufiicient tension has been applied to the basic yarn to rupture the frangible core strand 10. As tension on the core strand 10 is increased, the basic yarn elongates slightly, depending on the nature of the core strand, until the core strand breaks. The tension of the drafting process is then transferred to the wrapping strand, which from now on is the load bearing element. This transfer of tension tends to unwrap a certain portion of the falsely-twisted wrapping strand from the core strand, as indicated at 13 in FIGURE 2, and the combination of released tension and unwrapping action throws the segments of fractured core strand momentarily into a cursive configuration. The continued application of tension to the yarn, however, transforms the yarn of FIGURE 2 to the yarn of the invention, FIGURE 3, wherein the erstwhile core strand 10 now appears as a series of disconnected fragments disposed generally axially along the yarn, and the erstwhile wrapping strand 12 is now the load-bearing element consisting of slubs 16 and 18 and nubs 20, spaced apart by straight segments 15 of the strand 12.

A simple form of apparatus for producing the yarn of FIGURE 3 from the basic yarn of FIGURE '1 is shown in FIGURE 4, wherein rolls 30 and 32, together with rolls 38 and 40, constitute a set of drafting rolls. Normally, rolls 38 and 40 will be driven at a circumferential speed between 2.5 and 5 times the speed of rolls 30, and 32, whereby the strand of basic yarn 28 is drafted between the nips of rolls 30-32 and 3840 to form a variable denier novelty yarn 34, which in turn may be plied with another strand 36, of any desired nature, the yarns 34 and 36 passing through the nip of rolls 38-40 and being twisted together by a conventional ring spinning device to form the finished yarn 42, which is represented by FIGURE 5.

The above process will be illustrated by the following example.

Example 1 A yarn of the general nature of FIGURE 1 was made in the apparatus of FIGURE 6, which is a schematic cross-section of one apparatus used to make the yarn of FIGURE 1, as set forth in US. Patent 3,082,591. The apparatus comprises a vortex cell 50 with an air inlet 52, wrapping strand inlet 54, core strand inlet 56, and wrapped yarn outlet 58. The feed of the core strand 60 is controlled by rolls 62 and 64: the feed of the wrapping strand 66 by rols 68 and 70; and the take-up of the finished or basic yarn 72 by rolls 74 and 76.

A white 75 denier 2O filament acetate core strand was wrapped, at 90 p.s.i.g. air pressure, with a 70 denier 34 filament 2 ply black Superloft nylon strand (Leesona Corporation). There was no draft applied between rolls 6264 and rolls 74-76. Referring to FIGURE 1, approximately 5.75 yards of nylon wrapping strand 12 were disposed around each yard of core strand 10.

The resulting basic yarn was then twisted with a 75 denier 20 filament green acetate strand in the apparatus of FIGURE 4, with rolls 33 and 40 driven at 3.5 times the speed of rolls 30 and 32 to rupture the core strand at irregular intervals. The resultant yarn, FIGURE 5, was composed of the green acetate yarn 22 plied with the nylon strand 12, strand 12 being gathered on itself at intervals int-o slubs and nubs 16 and 18, and the original white core strand of the basic yarn appearing in the form of axially-disposed decorative fragments, bound to the main yarn by the wrappings of strand 12 and the ply strand 22.

In case even more texturized and decorative effect is desired, the yarn of FIGURE 1 may be combined with a third strand in the same apparatus in which it was formed --i.e., the apparatus of FIGURE 6, as illustrated by the following example.

Example 2 The basic yarn of Example 1, with a nylon wrap on an acetate core, was used as the core strand 60 in a vortex cell wrapping operation. In order to rupture the core strand, rolls 74 and 76 were set to take up the finished yarn at a rate 3.5 times as fast as the wrapped core strand was delivered by feed rolls 62 and 64. The same green acetate wrapping strand as in Example 1 was used as the wrapping strand 66, and was overfed to the vortex cell at a rate 6.9 times as fast as the strand 60.

The resulting yarn is shown in FIGURE 7, wherein the principal load-bearing nylon strand 12 is accumulated on itself into slubs 16 and 18: wrapped around this strand 12, with false twist in the form of doubledback loops 23 is the green acetate wrapping strand 22. The fragments of the original core strand 10 of the basic yarn again are axially bound to the yarn.

As indicated above, the basic yarn which precedes the yarn of this invention may also be tensioned in a corespinning operation. By core-spinning is meant a pro. cedure whereby a continuous strand (in this case, the basic yarn of FIGURE 1) is fed to a conventional drafting or spinning frame, together with a strand of roving comprising staple fibers, whereby the staple fibers are wrapped around and combined with the core strand. The basic yarn may also be ruptured to form the yarn of the invention by the processes conventionally used to wrap rubber or other elastic strands, such as the Well-known hollow spindle device. Since the fundamental process of this invention lies in rupturing a frangible core strand with a wrapping strand disposed thereabout in the form of doubled-back loops, various other expedients for applying the necessary breaking load, and for plying or combininb the resultant variable denier yarn with other yarns, strands, or rovings, will readily occur to those skilled in the art.

The description of the invention thus far has been confined to the sole use of tension to rupture the core strand. This process generally leads to situations wherein the denier changes in the product (slubs and nubs) are spaced apart a substantial distance in relation to the diameter of the yarn. In this light, FIGURES 3, 5, and 7 have been drawn with shortened horizontal axes to convey a maximum of detail in a short space. The denier variations 16 and 18 would actually be many inches apart if the scale of yarn diameter were applied to the yarn length. When the yarn of Example 2, for example, is stretched to make the product of FIGURE 7, the denier variations 16 and 18 are generally from one-half to three inches apart.

If it is desired to create slubs and nubs which are more closely spaced, although still randomly distributed, it is possible to pass the basic yarn of FIGURE 1 between the teeth of a pair of meshing gears which will crush the vulnerable core strand, or weaken at least a few filaments thereof, without substantially affiecting the wrapping strand. In this way, the core strand breaks under subsequent tension at frequent and short intervals, and the development of more frequent and more closely-spaced slubs and nubs is encouraged.

By the use of core strands, wrapping strands, and plying strands of different color, denier, and lustre, and by varying the degree of wrapping which eventuates into slubs and nubs, a wide variety of variable denier yarns can be produced in which the slubs and nubs are truly randomly distributed. In the process of making what I have herein called the basic yarn, according to my US. Patent 3,082,591, the wrapping strand is disposed around the core strand in a highly irregular and haphazard manner by an air vortex. The interentanglements of the loops of wrapping strand, which eventually give rise to slubs and nubs when the core strand is ruptured, are therefore casual and unpredictable, lending a pleasing randomness and lack of periodicity to the final yarn.

Having thus described my invention, I claim:

1. The process of making a novelty slub yarn which comprises combining with a frangible core strand at least one wrapping strand,

said Wrapping strand being disposed around said frangible core strand in the form of doubled-back loops wound with false twist for a multiplicity of turns around said core strand,

drafting the wrapped combination yarn under tension sufficient to rupture said frangible core strand, whereby a portion of the wrapping strand is formed into a multiplicity of spaced-apart slubs,

and another portion of the wrapping strand becomes the load-bearing element of the combination yarn.

2. The process according to claim 1 in which the tension is applied by a drafting operation in the process of feeding the wrapped combination yarn into a knitting machine.

3. The process according to claim 1 in which the tension is applied in a yarn-spinning device.

4. The process of making a plied novelty slub yarn which comprises combining with a frangible core strand at least one first wrapping strand,

said first wrapping strand being disposed around said frangible core strand in the form of doubled-back loops wound with false twist for a multiplicity of turns around said core strand,

drafting the wrapped combination yarn under tension suflicient to rupture said frangible core strand and to form a variable denier combination yarn,

while simultaneously plying said variable denier combination yarn with a third strand.

5. The process according to claim 4 in which the rupturing of the core strand and the plying with said third strand are done in a yarn-spinning device.

6. The process according to claim 5 in which said third strand is a strand of staple-fiber roving.

7. The process according to claim 4 in which the rupturing of the core strand and the plying with said third strand are done in a hollow-spindle elastic yarn wrapping device.

8. The process of making a wrapped novelty slub yarn which comprises combining with a frangible core strand at least one wrapping strand,

said wrapping strand being disposed around said frangible core strand in the form of doubled-back loops wound with false twist for a multiplicity of turns around said core strand,

drafting the wrapped combination yarn under tension sufficient to rupture said frangible core strand and to form a variable denier combination yarn,

while simultaneously wrapping around the combination yarn a third strand,

said third strand being disposed around said combination yarn in the form of doubled-back loops of said third strand,

wound with false twist for a multiplicity of turns around said combination yarn.

9. A novelty variable denier yarn characterized by randomized slubs and nubs which comprises a first textile strand of continuous filamentary material,

said first strand being at irregular intervals gathered on itself 'into a multiplicity of slubs and nubs in which the denier of said strand is greater than the denier of the rest of said strand,

together with disconnected segments of a second textile strand, 1 said fragments of second textile strand being noninterconnected with each other,

said fragments of second textile strand being generally axially disposed to the main axis of said variable denier yarn,

and being bound thereto by 'wrappings of said first strand.

10. A novel plied variable denier yarn which comprises the yarn of claim 9 plied with at least one other textile strand.

11. A novel wrapped variable denier yarn which comprises the yarn of claim 9 wrapped with a wrapping strand, said wrapping strand being disposed around the yarn of claim 9 in the form of doubled-back loops wound with false twist around the yarn of claim 9 for a multiplicity of turns.

References Cited UNITED STATES PATENTS 3,041,812 7/1962 Marshall 576 3,078,653 2/1963 Marshall 57--144 X 3,082,591 3/1963 Marshall 57-6 FRANK J. COHEN, Primary Examiner.

I. PETRAKES, Assistant Examiner. 

1. THE PROCESS OF MAKING A NOVELTY SLUB YARN WHICH COMPRISES COMBINING WITH A FRANGIBLE CORE STRAND AT LEAST ONE WRAPPING STRAND, SAID WRAPPING STRAND BEING DISPOSED AROUND SAID FRANGIBLE CORE STRAND IN THE FORM OF DOUBLED-BACK LOOPS WOUND WITH FALSE TWIST FOR A MULTIPLICITY OF TURNS AROUND SAID CORE STRAND, DRAFTING THE WRAPPED COMBINATION YARN UNDER TENSION SUFFICIENT TO RUPTURE SAID FRANGIBLE CORE STRAND, WHEREBY A PORTION OF THE WRAPPING STRAND IS FORMED INTO A MULTIPLICITY OF SPACED-APART SLUBS, AND ANOTHER PORTION OF THE WRAPPING STRAND BECOMES THE LOAD-BEARING ELEMENT OF THE COMBINATION YARN.
 9. A NOVELTY VARIABLE DENIER YARN CHARACTERIZED BY RANDOMIZED SLUBS AND NUBS WHICH COMPRISES A FIRST TEXTILE STRAND OF CONTINUOUS FILAMENTARY MATERIAL, SAID FIRST STRAND BEING AT IRREGULAR INTERVALS GATHERED ON ITSELF INTO A MULTIPLICITY OF SLUBS AND NUBS IN WHICH THE DENIER OF SAID STRAND IS GREATER THAN THE DENIER OF THE REST OF SAID STRAND, TOGETHER WITH DISCONNECTED SEGMENTS OF A SECOND TEXTILE STRAND, SAID FRAGMENTS OF SECOND TEXTILE STRAND BEING NONINTERCONNECTED WITH EACH OTHER, SAID FRAGMENTS OF SECOND TEXTILE STRAND BEING GENERALLY AXIALLY DISPOSED TO THE MAIN AXIS OF SAID VARIABLE DENIER YARN, AND BEING BOUND THERETO BY WRAPPINGS OF SAID FIRST STRAND. 